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A pair of middle-age identical twin brothers in Belgium, who were born deaf and were soon to go blind, were so distraught that they chose to be euthanized by lethal injection because they were unable to cope with the thought of never seeing one another again.

After spending their entire lives together, the brothers were euthanized by doctors at Brussels University Hospital in Jette on December 14 by lethal injection.

The latest case has become noteworthy in Belgium because the unidentified 45-year-olds weren't actually suffering from a terminal illness.

Under Belgium law, euthanasia is legal if patients making the decision can make their wishes clear and if a doctor judges that the patient is suffering from unbearable pain.

In 2011, 1,133 cases of euthanasia, mostly for terminal cancer, were recorded, and account for about 1 percent of all deaths in the European country, according to the official statistics.

However, the case of the twin brothers was unusual because neither twin was terminally ill or suffering from extreme physical pain.

According to The Telegraph, the two brothers, who have not been named but were pictured on Belgium television, were both cobblers and shared an apartment together.

"They were very happy. It was a relief to see the end of their suffering," Dr. David Dufour, of Brussels University Hospital, told RTL television news after the brothers decided to die in "full conscience" in December.

"They had a cup of coffee in the hall, it went well and a rich conversation," Dufour said.

"Then the separation from their parents and brother was very serene and beautiful," he added. "At the last there was a little wave of their hands and then they were gone."

Belgium was the second country in the world after the Netherlands to legalize euthanasia in 2002, and the law only applies to people over the age of 18.

However, a few days after the twins died, Belgium's ruling Socialists proposed a legal amendment that would allow the euthanasia of children and Alzheimer's patients.

"The idea is to update the law to take better account of dramatic situations and extremely harrowing cases we must find a response to," said Socialist leader Thierry Giet, according to The Telegraph.

If the proposed law is passed later this year, it will allow euthanasia to be "extended to minors if they are capable of discernment or affected by an incurable illness or suffering that we cannot alleviate".

In 2010, researchers from the Free University of Brussels found that most Belgians who choose euthanasia are younger, males and cancer patients and typically choose to die by barbiturates.

The practice of assisted suicide is allowed in three U.S. states: Montana, Oregon and Washington.

Americans have been largely divided on the idea of deliberately killing a person in pain, with many opposing the practice on religious grounds.

A Gallup survey conducted in 2011 found that physician-assisted suicide was the most controversial of all social issues. The poll found that 48 percent of those surveyed said that the practice is "morally wrong" and 45 percent said that it is "morally acceptable".